绮惧搧鏂囨。
绮惧搧鏂囨。
闀跨瘒闃呰鈥斺�斿尮閰嶉
Directions:
In this section, you are going to read a passage with ten statements attached to it. Each statement contains
information given in one of the paragraphs. Identify the paragraph from which the information is derived.
You may choose a paragraph more than once. Each paragraph is marked with a letter. Answer the questions
by marking the corresponding letter on
Answer Sheet 2.
Passage 1
Paper
鈥?/p>
More than Meets the Eye
A)
We
are
surrounded
by
so
much
paper
and
card
that
it
is
easy
to
forget
just
how
complex
it
is.
There
are
many
varieties and grades of paper materials, and whilst it is fairly easy to spot the varieties, it is far more difficult to spot
the grades.
B)
It
needs
to
be
understood
that
most
paper
and
card
is
manufactured
for
a
specific
purpose,
so
that
whilst
the
corn-flake packet may look smart, it is clearly not something destined for the archives. It is made to look good, but
only needs a limited life span. It is also much cheaper to manufacture than high grade card.
C) Paper can be made from an almost endless variety of cellulose
锛堢氦缁寸礌鍖栧悎鐗╋級
-based material which will include
many woods, cottons and grasses of which papyrus is an example and from where we get the word "paper". Many
of these are very specialized, but the preponderance of paper making has been from soft wood and cotton or rags,
with the bulk being wood-based.
Paper from Wood
D) In order to make wood into paper it needs to be broken down into fine strands. Firstly by powerful machinery and
then boiled with strong alkalies(
纰?/p>
) such as caustic soda, until a fine pulp of cellulose fibers is produced. It is from
this pulp that the final product is made, relying on the bonding together of the cellulose into layers. That, in a very
small nutshell, is the essence of paper making from wood. However, the reality is rather more complicated. In order
to
give
us
our
white
paper
and
card,
the
makers
will
add
bleach
and
other
materials
such
as
china
clay
and
additional chemicals.
E) A
further problem
with
wood
is
that
it
contains
a material
that
is
not
cellulose.
Something
called
lignin. This
is
essential for the tree since it holds the cellulose fibres together, but if it is incorporated into the manufactured paper
it presents archivists with a problem. Lignin eventually breaks down and releases acid products into the paper. This
will
weaken
the
bond
between
the
cellulose
fibers
and
the paper
will
become
brittle
and
look
rather brown
and
careworn. We have all seen this in old newspapers and cheap paperback books. It
has been estimated that
most
paperback books will have a life of no greater than fifty years, not what we need for our archives.
F) Since the lignin can be removed from the paper pulp during manufacture, the obvious question is "why is it left in
the paper". The answer lies in the fact that lignin makes up a considerable part of the tree. By leaving the lignin in
the pulp a papermaker can increase his paper yield from a tree to some 95%. Removing it means a yield of only
35%. It is clearly uneconomic to remove the lignin for many paper and card applications. It also means, of course,
that lignin-free paper is going to be more expensive.
G)
However,
it
is
nevertheless
what
the
archivist
must
look
for
in
his
supplies.
There
is
no
point
whatsoever
in
carefully placing our valuable artifacts in paper or card that is going to hasten their demise. Acid is particularly
harmful to photographic materials, causing them to fade and in some cases simply vanish!
H) So, how do we tell a piece of suitable paper or card from one that is unsuitable? You cannot do it by simply looking,
and rather disappointingly, you cannot always rely on the label.
"Acid-free" might be true inasmuch as a test on
the
paper
may
indicate
that
it
is
a
neutral
material
at
this
time.
But
lignin
can
take
years
before
it
starts
the
inevitable process of breaking down, and in the right conditions it will speed up enormously.
I) Added to this, as I have indicated earlier, paper may also contain other materials added during manufacture such as
bleach, china clay, chemical whiteners and size. This looks like a bleak picture, and it would be but for the fact that
there are suppliers who will guarantee the material that they sell. If you want
to be absolutely sure that you are
storing in, or printing on, the correct material then this is probably the only way.
J) Incidentally, acids can migrate from material to material. Lining old shoe boxes with good quality acid-free paper
will do little to guard the contents. The acid will get there in the end.
Paper from Rag
K) Paper is also commonly made from cotton and rag waste. This has the advantage of being lignin-free, but because
there is much less cotton and rag than trees, it also tends to be much more expensive than wood pulp paper. You
will still need to purchase from a reliable source though, since even rag paper and card can contain undesirable
additives.
L) A reliable source for quality rag papers is a recognized art stockiest. Many water color artists insist on using only